1. Field of the Invention
The present invention relates to a process for monitoring analog and digital mobile radio connections, and more particularly to the monitoring of such connections of a mobile radio network comprising a number of radio base stations in a mutually spaced arrangement in the form of a cellular system having overlapping radio ranges in which a predetermined number of radio ranges which are directly adjacent to one another form a group of radio ranges in which the total number of available frequency channels is repeated. More particularly, the frequency distribution plan for the radio base stations is designed to be such that like channel disturbances in a radio range, including an extended boundary zone, are substantially eliminated and at least the signaling in digital form between the radio base stations and the mobile subscriber stations is carried out by way of organization channels designed for duplex operation.
2. Description of the Prior Art
For a mobile radio network of this kind, such as is known for example through the German allowed published application No. 2,659,635, corresponding to British Pat. No. 1,562,964, an earlier application has proposed a realization for the transmission of the items of information containing the organization functions between the radio base stations and the mobile subscriber stations. Considerable significance is assigned to the monitoring of the radio connections, in particular with regard to the subscriber individual identification of the radio connections for the purpose of a realistic, error-free charge metering and the measurement and monitoring of the signal-to-noise ratio of the connection which permits the connection to be automatically broken or switched over as soon as a minimum permissible signal-to-noise ratio is undershot for a specific length of time.
Previously, the charge metering was derived exclusively from the received field strength. In this case, the charge metering can be falsely maintained by interference signals or overshooting.
In this case, identification and monitoring of the speech quality is impossible. Additional signaling must be transmitted in separate narrow-band channels, which result in a high filter expense.